TRAF1 regulates recruitment of lymphocytes and, to a lesser extent, neutrophils, myeloid dendritic cells and monocytes to the lung airways following lipopolysaccharide inhalation

A precise molecular subtyping of ulcerative colitis reveals the immune heterogeneity and predicts clinical drug responses

BACKGROUND AND AIMS

We sought to identify novel molecular subtypes of ulcerative colitis (UC) based on large-scale cohorts and establish a clinically applicable subtyping system for the precision treatment of the disease.

METHODS

Eight microarray profiles containing colon samples from 357 patients were utilized. Expression heterogeneity was screened out and stable subtypes were identified among UC patients. Immune infiltration pattern and biological agent response were compared among subtypes to assess the value in guiding treatment. The relationship between PRLR and TNFSF13B genes with the highest predictive value was further validated by functional experiments.

RESULTS

Three stable molecular subtypes were successfully identified. Immune cell infiltration analysis defined three subtypes as innate immune activated UC (IIA), whole immune activated UC (WIA), and immune homeostasis like UC (IHL). Notably, the response rate towards biological agents (infliximab/vedolizumab) in WIA patients was the lowest (less than 10%), while the response rate in IHL patients was the highest, ranging from 42 to 60%. Among the featured genes of subtypes, the ratio of PRLR to TNFSF13B could effectively screen for IHL UC subtype suitable for biological agent therapies (Area under curve: 0.961-0.986). Furthermore, we demonstrated that PRLR expressed in epithelial cells could inhibit the expression of TNFSF13B in monocyte-derived macrophages through the CXCL1-NF-κB pathway.

CONCLUSIONS

We identified three stable UC subtypes with a heterogeneous immune pattern and different response rates towards biological agents for the first time. We also established a precise molecular subtyping system and classifier to predict clinical drug response and provide individualized treatment strategies for UC patients.

Role of CD40(L)-TRAF signaling in inflammation and resolution-a double-edged sword

Cardiovascular diseases (CVD) and cardiovascular risk factors are the leading cause of death in the world today. According to the Global Burden of Disease Study, hypertension together with ischemic heart and cerebrovascular diseases is responsible for approximately 40% of all deaths worldwide. The major pathomechanism underlying almost all CVD is atherosclerosis, an inflammatory disorder of the vascular system. Recent large-scale clinical trials demonstrated that inflammation itself is an independent cardiovascular risk factor. Specific anti-inflammatory therapy could decrease cardiovascular mortality in patients with atherosclerosis (increased markers of inflammation). Inflammation, however, can also be beneficial by conferring so-called resolution, a process that contributes to clearing damaged tissue from cell debris upon cell death and thereby represents an essential step for recovery from, e.g., ischemia/reperfusion damage. Based on these considerations, the present review highlights features of the detrimental inflammatory reactions as well as of the beneficial process of immune cell-triggered resolution. In this context, we discuss the polarization of macrophages to either M1 or M2 phenotype and critically assess the role of the CD40L-CD40-TRAF signaling cascade in atherosclerosis and its potential link to resolution. As CD40L can bind to different cellular receptors, it can initiate a broad range of inflammatory processes that may be detrimental or beneficial. Likewise, the signaling of CD40L downstream of CD40 is mainly determined by activation of TRAF1-6 pathways that again can be detrimental or beneficial. Accordingly, CD40(L)-based therapies may be Janus-faced and require sophisticated fine-tuning in order to promote cardioprotection.

An altered sputum macrophage transcriptome contributes to the neutrophilic asthma endotype

Background

Neutrophilic asthma (NA) is a clinically important asthma phenotype, the cellular and molecular basis of which is not completely understood. Airway macrophages are long‐lived immune cells that exert important homeostatic and inflammatory functions which are dysregulated in asthma. Unique transcriptomic programmes reflect varied macrophage phenotypes in vitro. We aimed to determine whether airway macrophages are transcriptomically altered in NA.

Methods

We performed RNASeq analysis on flow cytometry‐isolated sputum macrophages comparing NA (n = 7) and non‐neutrophilic asthma (NNA, n = 13). qPCR validation of RNASeq results was performed (NA n = 13, NNA n = 23). Pathway analysis (PANTHER, STRING) of differentially expressed genes (DEGs) was performed. Gene set variation analysis (GSVA) was used to test for enrichment of NA macrophage transcriptomic signatures in whole sputum microarray (cohort 1 ‐ controls n = 16, NA n = 29, NNA n = 37; cohort 2 U‐BIOPRED ‐ controls n = 16, NA n = 47, NNA n = 57).

Results

Flow cytometry‐sorting significantly enriched sputum macrophages (99.4% post‐sort, 44.9% pre‐sort, p < .05). RNASeq analysis confirmed macrophage purity and identified DEGs in NA macrophages. Selected DEGs (SLAMF7, DYSF, GPR183, CSF3, PI3, CCR7, all p < .05 NA vs. NNA) were confirmed by qPCR. Pathway analysis of NA macrophage DEGs was consistent with responses to bacteria, contribution to neutrophil recruitment and increased expression of phagocytosis and efferocytosis factors. GSVA demonstrated neutrophilic macrophage gene signatures were significantly enriched in whole sputum microarray in NA vs. NNA and controls in both cohorts.

Conclusions

We demonstrate a pathophysiologically relevant sputum macrophage transcriptomic programme in NA. The finding that there is transcriptional activation of inflammatory programmes in cell types other than neutrophils supports the concept of NA as a specific endotype.

Therapeutic Potential of Combining IL-6 and TNF Blockade in a Mouse Model of Allergic Asthma

Combined anti-cytokine therapy is a promising therapeutic approach for uncontrolled steroid-resistant asthma. In this regard, simultaneous blockade of IL-4 and IL-13 signaling by Dupilumab (anti-IL-4Ra monoclonal antibody) was recently approved for severe eosinophilic asthma. However, no therapeutic options for neutrophilic asthma are currently available. Recent advances in our understanding of asthma pathogenesis suggest that both IL-6 and TNF may represent potential targets for treatment of severe neutrophilic asthma. Nevertheless, the efficacy of simultaneous pharmacological inhibition of TNF and IL-6 in asthma was not yet studied. To evaluate the potency of combined cytokine inhibition, we simultaneously administrated IL-6 and TNF inhibitors to BALB/c mice with HDM-induced asthma. Combined IL-6/TNF inhibition, but not individual blockade of these two cytokines, led to complex anti-inflammatory effects including reduced Th2-induced eosinophilia and less prominent Th17/Th1-mediated neutrophilic infiltrate in the airways. Taken together, our results provide evidence for therapeutic potential of combined IL-6/TNF inhibition in severe steroid-resistant asthma.

The Role of Tumor Necrosis Factor Associated Factors (TRAFs) in Vascular Inflammation and Atherosclerosis

TNF receptor associated factors (TRAFs) represent a family of cytoplasmic signaling adaptor proteins that regulate, bundle, and transduce inflammatory signals downstream of TNF- (TNF-Rs), interleukin (IL)-1-, Toll-like- (TLRs), and IL-17 receptors. TRAFs play a pivotal role in regulating cell survival and immune cell function and are fundamental regulators of acute and chronic inflammation. Lately, the inhibition of inflammation by anti-cytokine therapy has emerged as novel treatment strategy in patients with atherosclerosis. Likewise, growing evidence from preclinical experiments proposes TRAFs as potent modulators of inflammation in atherosclerosis and vascular inflammation. Yet, TRAFs show a highly complex interplay between different TRAF-family members with partially opposing and overlapping functions that are determined by the level of cellular expression, concomitant signaling events, and the context of the disease. Therefore, inhibition of specific TRAFs may be beneficial in one condition and harmful in others. Here, we carefully discuss the cellular expression and signaling events of TRAFs and evaluate their role in vascular inflammation and atherosclerosis. We also highlight metabolic effects of TRAFs and discuss the development of TRAF-based therapeutics in the future.

MicroRNA-127-5p attenuates severe pneumonia via tumor necrosis factor receptor-associated factor 1

Pneumonia is a persistent and pervasive disease, the effects of which can be severe. MicroRNA (miR)-127-5p has been utilized as a novel biomarker for the diagnosis of severe pneumonia. The present study aimed to investigate the function of miR-127-5p during severe pneumonia. An in vitro model of severe pneumonia in Ana-1 murine macrophages was established using lipopolysaccharide (LPS). Subsequently, reverse transcription-quantitative PCR and ELISA were performed to detect the mRNA and protein expression levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α. Western blotting was also performed to measure the activity of AKT and NF-κB. The results indicated that compared with the control group, LPS treatment increased TNF receptor-associated factor 1 (TRAF1) expression levels and reduced miR-127-5p expression levels. Furthermore, the results revealed that the 3'-untranslated region of TRAF1 was targeted by miR-127-5p. miR-127-5p mimic reduced LPS-induced increases in IL-1β, IL-6 and TNF-α expression by targeting TRAF1, which was potentially mediated by inactivation of the AKT and NF-κB signaling pathways. Collectively, the results demonstrated that miR-127-5p may attenuate severe pneumonia by reducing LPS-induced inflammatory cytokine production, and inactivating the AKT and NF-κB signaling pathways by targeting TRAF1.

Association of TRAF1/C5 Locus Polymorphisms with Epilepsy and Clinical Traits in Mexican Patients with Neurocysticercosis

Neurocysticercosis is caused by the establishment of Taenia solium cysts in the central nervous system. Murine cysticercosis by Taenia crassiceps is a useful model of cysticercosis in which the complement component 5 (C5) has been linked to infection resistance/permissiveness. This work aimed to study the possible relevance for human neurocysticercosis of single nucleotide polymorphisms (SNPs) in the C5-TRAF1 region (rs17611 C/T, rs992670 G/A, rs25681 G/A, rs10818488 A/G, and rs3761847 G/A) in a Mexican population and associated with clinical and radiological traits related to neurocysticercosis severity (cell count in the cerebrospinal fluid [CSF cellularity], parasite location and parasite load in the brain, parasite degenerating stage, and epilepsy). The AG genotype of the rs3761847 SNP showed a tendency to associate with multiple brain parasites, while the CT and GG genotypes of the rs17611 and rs3761847 SNPs, respectively, showed a tendency to associate with low CSF cellularity. The rs3761847 SNP was associated with epilepsy under a dominant model, whereas rs10818488 was associated with CSF cellularity and parasite load under dominant and recessive models, respectively. For haplotypes, C5- and the TRAF1-associated SNPs were, respectively, in strong linkage disequilibrium with each other; thus, these haplotypes were studied independently. For C5 SNPs, carrying the CAA haplotype increases the risk of showing high CSF cellularity 3-fold and the risk of having extraparenchymal parasites 4-fold, two conditions that are related to severe disease. For TRAF1 SNPs, the GA and AG haplotypes were associated with CSF cellularity, and the AG haplotype was associated with epilepsy. Overall, these findings support the clear participation of C5 and TRAF1 in the risk of developing severe neurocysticercosis in the Mexican population.

TRAF1 meditates lipopolysaccharide-induced acute lung injury by up regulating JNK activation

Acute lung injury (ALI) is served as a severe life-threatening disease. However, the pathogenesis that contributes to ALI has not been fully understood. Tumor necrosis factor receptor-associated factor 1 (TRAF1) interacts with multiple regulators, performing its diverse role in biological functions. However, the effects of TRAF1 on ALI remain unknown. In this study, we attempted to explore the role of TRAF1 in ALI progression. The findings suggested that TRAF1-knockout (KO) markedly attenuated LPS-induced severe mortality rate in murine animals. LPS-elicited histological alterations in pulmonary tissues were significantly alleviated by TRAF1-deletion. Additionally, TRAF1 knockout effectively attenuated lung injury, as evidenced by the reduced lung wet/dry (W/D) weight ratio, as well as decreased bronchoalveolar lavage fluid (BALF) protein levels and neutrophil infiltration. Meanwhile, TRAF1 deletion markedly lessened inflammation, oxidative stress and apoptosis in BALF and/or lung tissues. The levels of pro-inflammatory cytokines stimulated by LPS were down-regulated by TRAF1 ablation, along with the inactivation of nuclear factor κB (NF-κB). LPS-promoted reactive oxygen species (ROS) generation was decreased in TRAF1-KO mice, partly through the improvement of anti-oxidants. Apoptosis was also inhibited by TRAF1 deletion in lung tissues of LPS-challenged mice through the suppression of cleaved Caspase-3. Moreover, TRAF1 knockout significantly decreased c-Jun N-terminal kinase (JNK) activation and its down-streaming signal of c-Jun in pulmonary samples of LPS-induced mice. Importantly, the in vitro study suggested that promoting JNK activation markedly abrogated TRAF1 knockdown-attenuated inflammation, ROS production and apoptosis in LPS-exposed A549 cells. Therefore, our experimental results provided evidence that TRAF1 suppression effectively protected LPS-induced ALI against inflammation, oxidative stress and apoptosis through the suppression of JNK activity.

TRAF molecules in inflammation and inflammatory diseases

Purpose of Review

This review presents an overview of the current knowledge of TRAF molecules in inflammation with an emphasis on available human evidence and direct in vivo evidence of mouse models that demonstrate the contribution of TRAF molecules in the pathogenesis of inflammatory diseases.

Recent Findings

The tumor necrosis factor receptor (TNF-R)-associated factor (TRAF) family of cytoplasmic proteins was initially identified as signaling adaptors that bind directly to the intracellular domains of receptors of the TNF-R superfamily. It is now appreciated that TRAF molecules are widely employed in signaling by a variety of adaptive and innate immune receptors as well as cytokine receptors. TRAF-dependent signaling pathways typically lead to the activation of nuclear factor-κBs (NF-κBs), mitogen-activated protein kinases (MAPKs), or interferon-regulatory factors (IRFs). Most of these signaling pathways have been linked to inflammation, and therefore TRAF molecules were expected to regulate inflammation and inflammatory responses since their discovery in 1990s. However, direct in vivo evidence of TRAFs in inflammation and especially in inflammatory diseases had been lacking for many years, partly due to the difficulty imposed by early lethality of TRAF2^-/-, TRAF3^-/-, and TRAF6^-/- mice. With the creation of conditional knockout and lineage-specific transgenic mice of different TRAF molecules, our understanding about TRAFs in inflammation and inflammatory responses has rapidly advanced during the past decade.

Summary

Increasing evidence indicates that TRAF molecules are versatile and indispensable regulators of inflammation and inflammatory responses and that aberrant expression or function of TRAFs contributes to the pathogenesis of inflammatory diseases.

Single nucleotide polymorphisms in AGTR1, TFAP2B, and TRAF1 are not associated with the incidence of patent ductus arteriosus in Japanese preterm infants

BACKGROUND

Persistent patent ductus arteriosus (PDA) is a frequent complication in preterm infants. Single nucleotide polymorphisms (SNP) in several genes, including angiotensin II receptor, type 1 (AGTR1), transcription factor AP-2 beta (TFAP2B) and tumor necrosis factor receptor-associated factor 1 (TRAF1), have been reported to be associated with PDA in preterm infants. The aim of this study was to evaluate the relationships between PDA in preterm infants and polymorphisms in AGTR1, TFAP2B and TRAF1 in the Japanese population.

METHODS

The subjects consisted of 107 preterm infants with gestational age <32 weeks. Extremely low-birthweight infants were treated with prophylactic indomethacin during the first 24 h after birth. Five SNP, namely, rs5186 in AGTR1, rs987237 and rs6930924 in TFAP2B, and rs1056567 and rs10985070 in TRAF1, were genotyped using TaqMan SNP genotyping assays.

RESULTS

There were no significant differences in the distributions of the genotypes and allele frequencies of all studied SNP between the PDA group (n = 46) and the non-PDA group (n = 61).

CONCLUSIONS

There were no significant associations between the studied SNP and the incidence of PDA in Japanese preterm infants. These SNP may not be clinically important predisposing factors for PDA in Japanese preterm infants.

Cancer risk and mortality in asthma patients: A Swedish national cohort study

BACKGROUND

Previous studies found an increased risk of cancer in hospitalized asthma patients, but it is not known whether patients from primary health care show a similar risk pattern. In addition, it is unclear whether the diagnosis of asthma can influence the prognosis of subsequent cancer.

METHODS

Asthma patients were identified from Swedish inpatient, outpatient, and primary health care registers, and were linked to the Swedish Cancer Registry to identify subsequent diagnoses of cancer. Standardized incidence ratios (SIRs) were used to examine the risk of cancer in asthma patients compared with subjects without asthma. In addition, we used Cox proportional hazards regression to estimate hazard ratios (HRs) for mortality in patients with both asthma and cancer.

RESULTS

A total of 10 649 cancers were diagnosed in patients with previous asthma, with a SIR of 1.19 (95% CI 1.17-1.21). A total of 15 cancer sites showed an increased incidence, whereas two cancer sites showed a decreased risk. Non-allergic asthma showed the highest risk of cancer (SIR = 1.25, 95% CI 1.18-1.32), followed by unspecified asthma (SIR = 1.22, 95% CI 1.19-1.25), status asthmaticus (SIR = 1.19, 95% CI 1.02-1.39), and allergic asthma (SIR = 1.14, 95% CI 1.06-1.22). The risk of cancer was similarly increased in asthma patients diagnosed in primary health care and those diagnosed in hospitals. Cancer patients with previous asthma had increased mortality, with a HR of 1.55 (95% CI 1.50-1.60). HRs ranged from 1.09 to 1.94 for different sites/types of cancer.

CONCLUSIONS

Patients with asthma, irrespective of whether they were treated in primary health care or hospitals, had an increased risk of cancer. In addition, cancer patients with previous asthma had a worse prognosis compared with those without asthma, suggesting that these patients may require a multidisciplinary approach to manage the comorbidity.

Tumor necrosis factor receptor type I expression of CD4+ T cells in rheumatoid arthritis enables them to follow tumor necrosis factor gradients into the rheumatoid synovium

OBJECTIVE

The cytokine tumor necrosis factor (TNF) plays a central role in the pathogenesis of rheumatoid arthritis (RA), but its disease-specific effector mechanisms have not been fully elucidated. This study was undertaken to investigate the role of TNF in T cell accumulation and migration in the synovitic joints of RA patients.

METHODS

Vital tissue sections from rheumatoid synovium were generated using a horizontally oscillating microtome and were coincubated with fluorescence-labeled CD4+ T cells. Migration was detected by fluorescence and confocal microscopy. Migrating T cells were recovered from the tissue and analyzed for phenotype. Chemotaxis of CD4+ T cells from RA patients in response to increasing concentrations of TNF was analyzed in Transwell experiments.

RESULTS

CD4+ T cells from RA patients migrated into the tissue sections in significantly higher numbers than T cells from healthy controls. Migrating CD4+ T cells differed from nonmigrating ones in their increased expression of TNF receptor type I (TNFRI), which was expressed on a fraction of circulating CD4+ T cells from RA patients, but not from controls. CD4+ T cells from the peripheral blood of RA patients were also found to migrate along TNF concentration gradients ex vivo. Accordingly, blockade of either TNF or TNFRI nearly abrogated in vitro T cell migration in synovial tissue.

CONCLUSION

Our findings indicate that the interaction of TNF with TNFRI is pivotal for T cell migration in synovial tissue in vitro, and thereby suggest a relevant role of the cytokine for in vivo T cell trafficking to synovitic joints.

Leukocyte-specific protein 1 links TNF receptor-associated factor 1 to survival signaling downstream of 4-1BB in T cells

4-1BB is a member of the TNFR superfamily, which contributes to the activation of signaling pathways required for the survival of activated and memory T cells. We have shown previously that TRAF1, an adaptor protein recruited to 4-1BB, is required for 4-1BB-mediated CD8 T cell survival in vivo. With the use of a proteomics approach in primary T cells, we have identified LSP1 as a novel protein recruited to the 4-1BB signaling complex in a TRAF1-dependent manner. Further characterization of the interaction between TRAF1 and LSP1 revealed that LSP1 requires the TRAF-N domain of TRAF1 for direct association. Similarly to TRAF1(-/-) T cells, LSP1(-/-) T cells exhibit impaired ERK activation following stimulation through 4-1BB and consequently, are unable to down-modulate expression of the proapoptotic Bcl-2 family member Bim. Moreover, we demonstrate that the absence of LSP1 expression leads to defective expansion and survival of T cells in response to 4-1BB stimulation. Thus, we have identified LSP1 as a new mediator involved in 4-1BB signaling and T cell survival. Collectively, our work shows that TRAF1 and LSP1 cooperate downstream of 4-1BB to activate ERK signaling and down-modulate the levels of Bim leading to enhanced T cell survival.

TLR2, but not TLR4, is required for effective host defence against Chlamydia respiratory tract infection in early life

Chlamydia pneumoniae commonly causes respiratory tract infections in children, and epidemiological investigations strongly link infection to the pathogenesis of asthma. The immune system in early life is immature and may not respond appropriately to pathogens. Toll-like receptor (TLR)2 and 4 are regarded as the primary pattern recognition receptors that sense bacteria, however their contribution to innate and adaptive immunity in early life remains poorly defined. We investigated the role of TLR2 and 4 in the induction of immune responses to Chlamydia muridarum respiratory infection, in neonatal wild-type (Wt) or TLR2-deficient (^−/−), 4^−/− or 2/4^−/− BALB/c mice. Wt mice had moderate disease and infection. TLR2^−/− mice had more severe disease and more intense and prolonged infection compared to other groups. TLR4^−/− mice were asymptomatic. TLR2/4^−/− mice had severe early disease and persistent infection, which resolved thereafter consistent with the absence of symptoms in TLR4^−/− mice. Wt mice mounted robust innate and adaptive responses with an influx of natural killer (NK) cells, neutrophils, myeloid (mDCs) and plasmacytoid (pDCs) dendritic cells, and activated CD4⁺ and CD8⁺ T-cells into the lungs. Wt mice also had effective production of interferon (IFN)γ in the lymph nodes and lung, and proliferation of lymph node T-cells. TLR2^−/− mice had more intense and persistent innate (particularly neutrophil) and adaptive cell responses and IL-17 expression in the lung, however IFNγ responses and T-cell proliferation were reduced. TLR2/4^−/− mice had reduced innate and adaptive responses. Most importantly, neutrophil phagocytosis was impaired in the absence of TLR2. Thus, TLR2 expression, particularly on neutrophils, is required for effective control of Chlamydia respiratory infection in early life. Loss of control of infection leads to enhanced but ineffective TLR4-mediated inflammatory responses that prolong disease symptoms. This indicates that TLR2 agonists may be beneficial in the treatment of early life Chlamydia infections and associated diseases.

Cyptoporus polysaccharide prevents lipopolysaccharide-induced acute lung injury associated with down-regulating Toll-like receptor 2 expression

AIM OF THE STUDY

To evaluate the effects and the possible mechanism of Cryptoporus polysaccharides (CP) extracted from fruiting body of Cryptoporus volvatus in lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats and mice.

MATERIALS AND METHODS

Acute lung injury was induced by intratracheally instillation of LPS into lung in either rats or mice, assessing leukocyte numbers and myeloperoxidase activity in bronchoalveolar lavage fluid, as well as evaluating cytokines mRNA and protein expressions, and Toll-like receptor 2 (TLR(2)) and nuclear factor (NF)-κB mRNA levels in the lung tissues of mice. Vascular permeability and edema of lung in mice, and arterial blood gas in rats were also performed.

RESULTS

In ALI, CP-treated mice and rats exhibited significantly reduced leukocyte invasion, myeloperoxidase activity, vascular permeability, edema of lung, as well as tumor necrosis factor-α and Interleukin-1β mRNA and protein expressions in the lung tissues compared with vehicle-treated mice. TLR(2) and NF-κB mRNA levels of the lung tissues were decreased in CP-treated mice in response to LPS. And decline in arterial blood gas was recovered in CP-treated rats.

CONCLUSIONS

Our results supported a protective role of CP in ALI and suggested that the reduction of the activation of TLR(2) and NF-κB signal pathway in lung injury may be relavant to the pretreatment of CP.

Single early prenatal lipopolysaccharide exposure prevents subsequent airway inflammation response in an experimental model of asthma

AIMS

There has been emerging interest in the prenatal determinants of respiratory disease. In utero factors have been reported to play a role in airway development, inflammation, and remodeling. Specifically, prenatal exposure to endotoxins might regulate tolerance to allergens later in life. The present study investigated whether prenatal lipopolysaccharide (LPS) administration alters subsequent offspring allergen-induced inflammatory response in adult rats.

MAIN METHODS

Pregnant Wistar rats were treated with LPS (100 μg/kg, i.p.) on gestation day 9.5 and their ovariectomized female offspring were sensitized and challenged with OVA later in adulthood. The bronchoalveolar lavage (BAL) fluid, peripheral blood, bone marrow leukocytes and passive cutaneous anaphylaxis were evaluated in these 75-day-old pups.

KEY FINDINGS

OVA sensitized pups of NaCl treated rats showed an increase of leucocytes in BAL after OVA challenge. This increase was attenuated, when mothers were exposed to a single LPS injection early in pregnancy. Thus, LPS prenatal treatment resulted in (1) lower increased total and differential (macrophages, neutrophils, eosinophils and lymphocytes) BAL cellularity count; (2) increased number of total, mononuclear and polymorphonuclear cells in the peripheral blood; and (3) no differences in bone marrow cellularity or passive cutaneous anaphylaxis.

SIGNIFICANCE

In conclusion, female pups treated prenatally with LPS presented an attenuated response to experimentally-induced asthma. We observed reduced immune cell migration from peripheral blood to the lungs, with no effect on the production of bone marrow cells or antibodies. It was suggested that inflammatory events such as exposure to LPS in early fetal life can attenuate allergic inflammation in the lung, which is a common symptom in asthma.

Tumor necrosis factor receptor-associated factor 1 (TRAF1) deficiency attenuates atherosclerosis in mice by impairing monocyte recruitment to the vessel wall

BACKGROUND

Members of the tumor necrosis factor superfamily, such as tumor necrosis factor-alpha, potently promote atherogenesis in mice and humans. Tumor necrosis factor receptor-associated factors (TRAFs) are cytoplasmic adaptor proteins for this group of cytokines.

METHODS AND RESULTS

This study tested the hypothesis that TRAF1 modulates atherogenesis in vivo. TRAF1(-/-)/LDLR(-/-) mice that consumed a high-cholesterol diet for 18 weeks developed significantly smaller atherosclerotic lesions than LDLR(-/-) (LDL receptor-deficient) control animals. As the most prominent change in histological composition, plaques of TRAF1-deficient animals contained significantly fewer macrophages. Bone marrow transplantations revealed that TRAF1 deficiency in both hematopoietic and vascular resident cells contributed to the reduction in atherogenesis observed. Mechanistic studies showed that deficiency of TRAF1 in endothelial cells and monocytes reduced adhesion of inflammatory cells to the endothelium in static and dynamic assays. Impaired adhesion coincided with reduced cell spreading, actin polymerization, and CD29 expression in macrophages, as well as decreased expression of the adhesion molecules intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in endothelial cells. Small interfering RNA studies in human cells verified these findings. Furthermore, TRAF1 messenger RNA levels were significantly elevated in the blood of patients with acute coronary syndrome.

CONCLUSIONS

TRAF1 deficiency attenuates atherogenesis in mice, most likely owing to impaired monocyte recruitment to the vessel wall. These data identify TRAF1 as a potential treatment target for atherosclerosis.

Determination of genetic predisposition to patent ductus arteriosus in preterm infants

OBJECTIVE

Patent ductus arteriosus is a common morbidity associated with preterm birth. The incidence of patent ductus arteriosus increases with decreasing gestational age to approximately 70% in infants born at 25 weeks' gestation. Our major goal was to determine if genetic risk factors play a role in patent ductus arteriosus seen in preterm infants.

METHODOLOGY

We investigated whether single-nucleotide polymorphisms in genes that regulate smooth muscle contraction, xenobiotic detoxification, inflammation, and other processes are markers for persistent patency of ductus arteriosus. Initially, 377 single-nucleotide polymorphisms from 130 genes of interest were evaluated in DNA samples collected from 204 infants with a gestational age of <32 weeks. A family-based association test was performed on genotyping data to evaluate overtransmission of alleles.

RESULTS

P values of <.01 were detected for genetic variations found in 7 genes. This prompted additional analysis with an additional set of 162 infants, focusing on the 7 markers with initial P values of <.01, and 1 genetic variant in the angiotensin II type I receptor previously shown to be related to patent ductus arteriosus. Of the initial positive signals, single-nucleotide polymorphisms in the transcription factor AP-2 beta and tumor necrosis factor receptor-associated factor 1 genes remained significant. Additional haplotype analysis revealed genetic variations in prostacyclin synthase to be associated with patent ductus arteriosus. An angiotensin II type I receptor polymorphism previously reported to be associated with patent ductus arteriosus after prophylactic indomethacin administration was not associated with the presence of a patent ductus arteriosus in our population.

CONCLUSIONS

Overall, our data support a role for genetic variations in transcription factor AP-2 beta, tumor necrosis factor receptor-associated factor 1, and prostacyclin synthase in the persistent patency of the ductus arteriosus seen in preterm infants.

Inhibitory effects of flavonoids extracted from licorice on lipopolysaccharide-induced acute pulmonary inflammation in mice

Airway inflammation plays important roles in the pathogenesis of acute respiratory distress syndrome (ARDS), asthma and chronic obstructive pulmonary disease (COPD), and anti-inflammatory treatment effectively improves the symptoms of these diseases. To develop the potentially therapeutic compounds for the treatment of pulmonary inflammation, we investigated the effects of licorice flavonoids (LF) extracted from the roots of Glycyrrhiza uralensis (licorice) on lipopolysaccharide (LPS)-induced acute pulmonary inflammation in mice. Acute pulmonary inflammation was induced by intracheal instillation with LPS, treatment with LF at dosages of 3, 10 and 30 mg/kg significantly reduced the LPS-induced inflammatory cells, including neutrophils, macrophages and lymphocytes accumulation in bronchoalveolar lavage fluids (BALF), among these inflammatory cells, LF predominately inhibited neutrophil infiltration, and the maximal effect (30 mg/kg) was as comparable as dexamethasone treatment at 1 mg/kg. Consistent with its effects on neutrophil infiltration, LF treatment significantly increased LPS-induced BALF superoxide dismutase activity, and significantly decreased lung myeloperoxidase activity as well. Furthermore, treatment with LF at 30 mg/kg significantly reduced LPS-induced lung TNFalpha and IL-1beta mRNA expression at 6 h and 24 h after LPS instillation, respectively. Finally, LF at different dosages not only significantly decreased the elevation of lung water content, but also markedly attenuated LPS-induced histological alteration. Therefore, we suggest that LF effectively attenuates LPS-induced pulmonary inflammation through inhibition of inflammatory cells infiltration and inflammatory mediator release which subsequently reduces neutrophil recruitment into lung and neutrophil-mediated oxidative injury, and this study provides with the potential rationale for development of anti-inflammatory compounds from flavonoid extracts of licorice.

TNF receptor-associated factor 1 expressed in resident lung cells is required for the development of allergic lung inflammation

TNF is a major therapeutic target in a range of chronic inflammatory disorders, including asthma. TNFR-associated factor (TRAF)1 is an intracellular adaptor molecule important for signaling by TNFR. In this study, we investigated the role of TRAF1 in an adoptive transfer model of allergic lung inflammation. Mice deficient in TRAF1 (TRAF1(-/-)) and wild-type (WT) control animals were adoptively transferred with WT OVA-immune CD4(+) T cells, exposed to an aerosol of LPS-free OVA, and analyzed for the development of allergic lung inflammation. In contrast to WT mice, TRAF1(-/-) recipients failed to display goblet cell hyperplasia, eosinophilic inflammation, and airway hyperresponsiveness in this model of asthma. Neither T cell recruitment nor expression of the proinflammatory cytokines IL-4, IL-5, IL-13, or TNF occurred in the lungs of TRAF1(-/-) mice. Although purified myeloid TRAF1(-/-) dendritic cells (DCs) exhibited normal Ag-presenting function and transmigratory capacity in vitro and were able to induce OVA-specific immune responses in the lung draining lymph nodes (LNs) following adoptive transfer in vivo, CD11c(+)CD11b(+) DCs from airways of TRAF1(-/-) recipients were not activated, and purified draining LN cells did not proliferate in vitro. Moreover, transfer of WT or TRAF1(-/-) DCs failed to restore T cell recruitment and DC activation in the airways of TRAF1(-/-) mice, suggesting that the expression of TRAF1 in resident lung cells is required for the development of asthma. Finally, we demonstrate that T cell-transfused TRAF1(-/-) recipient mice demonstrated impaired up-regulation of ICAM-1 expression on lung cells in response to OVA exposure.